Enamel removing means



C. C. RHODES ENAMEL REMOVING MEANS Filed June 8, '1939 29. Mimi WURKIN'G.

Patented Sept. 16, 1941 UNITED STATES PATENT OFFICE 4 Claims.

The invention relates to devices for distorting enamel coated metallic articles to remove the enamel coating from the metal.

As is well known to those familiar with the metal enamelling art, an occasional article or portion thereof has to be discarded by reason of defects or imperfections in the enamel coating. In order that the metal may be salvaged and adapted to be melted for further use, it is necessary that the enamel be removed since the presence of vitreous materials in perceptible quantities in the molten mass results in an undesirable low grade product suitable for very limited use, such as for counter-weights for windows and the like wherein the material is not subjected to strain. Although the ratio of such defectively enamelled articles to the total output is relatively small, the aggregate is sufficiently large that it is desirable and economical to salvage the metal in such condition that upon melting it provides suitable standard or high grade material.

There are numerous devices extant for mechanically treating defectively enamelled metal articles to remove the enamel. Such devices comprise means such as cooperating rollers or the like operable in general to distort the metal base by bending and not by stretching or elongation thereof upon passing the articles between the rollers. Distortion by bending is effective to break ofi the outer portions of the brittle enamel, but is ineffective to completely detach or remove the inner lportions of the enamel because of its close adhesion to the metal and also because such bending produces only slight and in most cases no movement at all of the outer surfaces of the metal relative to the inner surfaces of the enamel adhering thereto.

In other words de-enamellng, accomplished by bending only, does not get the metal sufliciently freed from the enamel to avoid its substantial contamination by the latter when melted up prior to rolling it for further use. 'I'he known methods of mechanically removing the enamel consist largely if not entirely in distortion by bending, and have been unsuccessful since the resulting scrap when melted is of low grade.

The invention contemplates complete detachment of the enamel primarily by distortion of the entire metal base by substantially stretching every portion thereof, since distortion by stretching effectively destroys all cohesion between the enamel and the metal base and any bending of the base is only incidental to the stretching thereof. The ductility of the metal base being much greater than that of its vitreous enamel coating, stretching or elongation of the metal necessarily produces a substantial relative movement of the surface areas of the metal relative to the inner surface areas of the enamel coatings and obviously this stretching destroys all cohesion of the metal and enamel, particularly if the stretching is entire and in a plurality of diierent directions.

The invention also contemplates the provision of novel mechanical means for stretching the metal as described to remove the enamel, such means including oppositely rotating strong rigid rollers, powerfully driven and equipped with knobs, studs, gear teeth, or other intervening protrusions set the proper distance apart to allow the enamelled articles to be fed between them and to substantially deform the metal base of such articles as they are passed between the rollers. The protrusions on the rollers are sumcient in number and so arranged for proper engagement with the articles to be distorted thereby that the metal base is stretched in an amount such that the enamel will come off the metal cleanly, leaving only a few loosely clinging small and dust-like particles which are easily brushed off.

The invention has as one of its objects the provision of a novel method for destroying the cohesion between the metal base and the enamel coatings of articles of the kind described and it also provides novel means operable to practice the method by stretching the entire metal base substantially in a plurality of directions.

It is anotherobject of the invention to provide an improved device for distorting objects of the kind described consisting of a metal base coated with enamel, the device being operable to successively stretch different portions of the articles in a plurality of different directions to accomplish complete detachment of the coating of enamel from the metal base of such articles.

A further object of the invention is the provision of a device including a pair of rollers providing a plurality oi' projections or protrusions so arranged as to stretch all portions of enamelled articles of the kind described as they are advanced between the rollers, the stretching being in excess of the ductility or elastic limit of the enamel.

A still further object of the invention is the provision of metal distortion devices of the kind described which are simple, inexpensive, durable, and satisfactory for their intended purposes.

Many other objects and advantages of the method and construction herein shown and described will be obvious to those skilled in the art from the disclosure herein given.

'Io-this end my invention consists in the novel construction, arrangement, and combination of parts herein shown and described and more par.. ticularly pointed out in the claims.

In the drawing wherein like reference characters indicate like or corresponding parts:

Fig. l is a front elevational view of a device embodying the principles of the invention; and

Fig. 2 is an end elevation of the device shown in Fig. 1.

Referring now more particularly to the drawing forming a part of the specification, a supporting frame designated by the letter F provides a mounting for the spindles of cooperating upper and lower rollers respectively designated as A and A1, the roller A being adapted to be actuated by means of a sprocket wheel or gear G mounted on one projecting end of the spindle supporting said roller A. The rollers A and A1 are spaced apart as shown and are preferably of the same diameter. Rotation of the roller A in either direction correspondingly rotates the roller A1 in the opposite direction by reason of a pair of meshing gears G1 respectively mounted on the spindles supporting the rollers A and A1, it being understood that the gears G1 are preferably of the same diameter and that the rollers A and A1 are also preferably of equal diameter in order that the peripheries of said rollers may be oppositely rotated at equal rates.

The rollers A and A1 are each provided with a plurality of knobs, studs, or similar projections B, arranged in rows extending longitudinally of the rollers. The knobs B may take the form of a segment of a sphere as shown or they may be in the form of cones or pyramids having rounded apices. The knobs B preferably comprise the heads of screw bolts threadedly mounted in radially extending apertures in the rollers although they may if desired be formed as an integral part of such rollers. The longitudinally extending rows of knobs B are preferably equally spaced circumferentially with the knobs in alternative rows circumferentially aligned and staggered relative to the knobs in the next adjacent circumferential and longitudinal rows. The meshing of the gears G1 is such that each longitudinal row of knobs B on the rollers A and A1 are successively positioned midway between adjacent longitudinal rows of knobs B on the other roller as rotation of the rollers brings each longitudinal row of knobs into their closest proximity to the opposite roller. If the articles to be deenamelled are of irregular configuration, they are flattened out upon being fed between the rollers A and A1. The amount of protrusion of the knobs B, their spacing in the longitudinal rows and the circumierential spacing of said rows are such that an article as it passes between the .rollers is successively engaged by a longitudinal row of knobs B on the roller A and two adjacent longitudinal rows of knobs on the roller A1 and then by a longitudinal row of knobs on the roller A1 and the two adjacent longitudinal rows of knobs on the roller A and so on. The ductile metal bases of such articles are thereby stretched and distorted to form a plurality of spherical shaped areas, convex on one side and concave on the other. Obviously, the articles passed between the rollers as described will emerge with as many distorted spherical shaped areas as the number of knobs of both rollers operatively engaging the articles. Alternate rows of the distorted areas corresponding to the longitudinal rows of the knobs B will be oppositely concave-convex. An article having been initially engaged by the knobs B of rollers A and A1 as described will be distorted by the stretching of its metal base to provide the various spherical shaped areas. The stretching of the metal is accomplished without any change in the over all lateral or longitudinal dimensions of the article since it is held by the knobs against shortening in either direction and permits a maximum of distortion by stretching. The spacing of the knobs in each row and the circumferential spacing of the rows are suiliciently close and the knobs project in an amount such that every portion of the metal base of an article will be stretched in an amount substantially in excess of the elastic limit or ductllity of the enamel. Such distortion by stretching thereby completely destroys the adhesion of the enamel, causing it to break away and leave only a few free particles clinging to the metal base which are easily removed by means of a brush.

Obviously, the spacing of the knobs B longitudinally and circumferentially, the amount of protrusion of said knobs, and the spacing and diameter of the rollers best adapted to remove the enamel depend upon the thickness of the metal bases of the articles to be de-enamelled and are such that every portion of the metal bases are distorted by stretching far beyond the elastic limit of the enamel to be removed.

Thus, it will be seen that the invention provides a novel method adapted to completely deenamel articles of the kind described by mechanical action and the invention also provides novel mechanism adapted to practice the method.

Having thus described my invention, it is obvious that various immaterial modications may be made in the same without departing from the scope of my invention; hence, I do not wish to be understood as limiting niyself to the exact form, construction, arrangement, and combination of parts herein shown and described or uses mentioned.

I claim:

1. Apparatus for treating waste enamelled articles comprising a pair of rollers, a frame on which said rollers are mounted in spaced relation, means operable to rotate said rollers in opposite directions, said rollers each having a plurality of uniformly spaced projecting substantially hemi-spherical elements or knobs, the arrangement andspacing of said elements being such that as revolution of said rollers successively brings each element into close proximity with the opposite roller it is thereby positioned between and closely and substantially equally spaced from and is loosely intermeshed with the elements provided by said opposite roller.

2. Apparatus for treating waste enamelled articles comprising a pair of rollers of equal diameters, a frame on which said rollers are mounted in parallel spaced relation, means operable to rotate said rollers in opposite directions, said rollers each having a plurality of projecting substantially hemi-spherical elements or knobs arranged in longitudinal and circumferential rows, the spacing of said elements in said rows and the spacing of said rows being identical on both rollers, the elements of each roller being so positioned relative to the elements of the other that revolution of said rollers successively brings each longitudinal row of elements into close proximity with the opposite roller approximately midway between two adjacent longitudinal rows of elements of said opposite roller and the circumfe'rntial rows of elements approximately equally spaced from the contiguous circumferential rows of elements on the opposite roller, the spacing of said rollers being slightly greater than the amount said elements respectively project from the rollers, the elements on one roller loosely intermeshing with the elements on the other roller, said spacing being sufficient to permit articles of the kind described to pass between each roller and the ends of the elements projecting from the other roller when said elements are in closest proximity to the opposite roller.

3. The method of de-enamelling articles comprising a metal base having a coating of vitreous enamel of the kind described which consists in distorting contiguous portions of the metal base by a single operation to form a plurality of oppositely protruding concavo-convex projections each having a height and an area such that the metal base comprising each projection is stretched beyond the elastic limit of the enamel adhering thereto.

4. The method of removing enamel coatings from a metal plate, which consists in stretching all portions of the plate in an amount exceeding the elastic limit of the enamel adhering thereto, said stretching being accomplished by forcing a plurality of portions of a relatively narrow transversely extending portion or section adjacent one end of the plate laterally in one direction to form a row of transversely spaced concavo-convex projections protruding from one side, then similarly forming a contiguous row of transversely extending concavo-convex projections protruding from the opposite side, then similarly forming a row of projections contiguous to the second row by protruding from the opposite side of the plate, then continuing the operation successively on contiguous limited transverse sections of the plate to form alternate transverse rows of projections until the entire plate is distorted as described and presents transverse rows of projections with alternate rows oppositely protruding and the projections of alternate rows being aligned longitudinally.

CLAUDE C. RHODES. 

